Q.63 Which of the following is/are phanerogamic parasite(s)?
(A) Cuscuta reflexa
(B) Orobanche cernua
(C) Ocimum sanctum
(D) Santalum album

The phanerogamic parasites in this question are Cuscuta reflexa (A), Orobanche cernua (B) and Santalum album (D); Ocimum sanctum (C) is not a parasite.​​

Introduction

Phanerogamic parasites are flowering plants that parasitize other plants using specialized organs called haustoria to absorb water and nutrients from their hosts. They include both total and partial parasites, attacking either stems or roots, and are very important for competitive exam MCQs in botany and agriculture.​

Option (A) Cuscuta reflexa

• Nature of plant: Cuscuta is a leafless, rootless, yellow to orange twining plant that completely depends on the host for water and organic food, making it an obligate stem holoparasite.​

• Why phanerogamic parasite: It is a flowering angiosperm that forms haustoria on the host stem, thus classified as a phanerogamic (flowering) stem parasite; Cuscuta reflexa is a standard textbook example.​

Therefore, option (A) Cuscuta reflexa is a phanerogamic parasite.

Option (B) Orobanche cernua

• Nature of plant: Species of Orobanche (broomrapes) are obligate, non‑photosynthetic root holoparasites that lack chlorophyll and live attached to host roots. Orobanche cernua specifically parasitizes roots of crops like tobacco and other species.​

• Why phanerogamic parasite: Orobanche species are flowering angiosperms that produce characteristic broomrape spikes and are classic root phanerogamic parasites in the family Orobanchaceae.​

Therefore, option (B) Orobanche cernua is a phanerogamic parasite.

Option (C) Ocimum sanctum

• Nature of plant: Ocimum sanctum (Tulsi/Holy basil) is an aromatic, medicinal shrub of family Lamiaceae, widely cultivated for its essential oils and therapeutic properties.​

• Not a parasite: Tulsi is fully autotrophic with functional roots, stems and leaves, and does not form haustoria or depend on other plants for nutrition, so it is not parasitic, and certainly not a phanerogamic parasite.​

Therefore, option (C) Ocimum sanctum is NOT a phanerogamic parasite.

Option (D) Santalum album

• Nature of plant: Santalum album (sandalwood) is a woody tree in family Santalaceae that forms haustorial connections with roots of neighboring plants to obtain water and minerals.​

• Type of parasite: It is a partial root parasite (hemiparasite) because it contains chlorophyll and can photosynthesize but still parasitizes host roots for inorganic nutrients, making it a recognized phanerogamic root parasite.​

Therefore, option (D) Santalum album is a phanerogamic parasite.

Final exam-oriented answer

• (A) Cuscuta reflexa – Phanerogamic stem holoparasite ✔​

• (B) Orobanche cernua – Phanerogamic root holoparasite ✔​

• (C) Ocimum sanctum – Autotrophic medicinal herb, not a parasite ✘​

• (D) Santalum album – Phanerogamic partial root parasite (hemiparasite) ✔​

Correct choice set: (A), (B) and (D).